In nematodes an alternative third larval stage, often called the dauer stage, allows the animals to weather periods of low food availibility (if free living) or to disperse (if parasitic. Recently, studies in the nematode Caenorhabditis elegans have indicated that mutations in several genes that control the entry into and exit from the dauer stage have profound effect upon the effect upon the life span of the animal. We have recently identified a mutation affecting the expression of an unusual catalase gene, ctl-1, in C. elegans that in preliminary experiments acts as if it is downstream of the genes in the dauer pathway. Messenger RNA coding for this catalase is elevated in dauer larvae. The mutation affecting ctl-1 expression causes the early death of dauer larvae and prevents the life-span extention of the dauer (daf) mutations. The hypothesis driving the proposed research is that this catalase (along with superoxide dismutase) is an important final target (perhaps the most important target) of the dauer pathway in the control of life-span. Specific aims designed to establish this hypothesis are 1) to characterize molecularly the ctl-1 and ctl-2 (s); 2) to complete the characterization of the effect of the ctl-1 mutation on life-span; and 3) to examine the expression of ctl-1 and ctl-2 using antibodies and GFP fusions and to test the functionality of the C. elegans catalases in yeast.